I just read this on the RME site which may be of interest. I see now why Lee suggests installing the 2 sata drives (for samples) in a Raid 0 configuration on the ICH5 Sata port (so it bypasses the PCI bus)
"The Promise Fasttrack Controller causes performance problems when using the Hammerfall. An operation at lower latencies generates clicks and pops.
Comment: To achieve the highest rating in benchmark tests the Fasttrack controller hogs the PCI bus, thus impacts the data transfer of other PCI devices (the Hammerfall.) This is true for both the PCI-card and the on-board version (as on the MSI K7T266 Pro), but not true for the majority of 'normal' Promise RAID controllers.
Promise offers a software tool to set up the controller. Move the slider labeled PCI Bus Utilization from 100% (right side, default) to about 75%. This solves the problems."